head to head
Total War: Warhammer III asks more than Portal, and the gap is reads.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
A campaign strategy game where army composition meets real-time micro.
Portal leans Optimization (Pure Optimization); Total War: Warhammer III leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Portal
Portal placement timing modest.
Total War: Warhammer III
Real-time micro of units rewards quick hands.
Total War: Warhammer III leans clearly harder on reads.
Portal
No adversary modeling player.
Total War: Warhammer III
Campaign AI scripted; multiplayer battles adapt.
Total War: Warhammer III leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Total War: Warhammer III
Campaign events and battle terrain vary.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
Pure puzzle-solving optimization.
Total War: Warhammer III
Army comp, magic, and campaign economy are solvable.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.